实时荧光定量PCR在植物病害流行学中的应用

实时荧光定量PCR广泛应用于植物病理学研究的各个领域。近年来已开始应用于植物病害流行学的定量研究中,本文对近年来实时荧光定量PCR技术在病菌初始菌源的定量分析、病害流行动态的监测、寄主抗病性的快速鉴定和植物病原菌的抗药性监测等方面的应用进行了综述。     

植物病害时空流行动态模拟模型的构建

 一个描述在二维空间中单一种植或混合种植的植物群体内病害时、空流行动态的计算机随机模拟模型构建完成。模型由寄主、病原2个组分和病斑产孢、孢子传播、孢子着落、孢子侵染、病斑潜育、寄主生长、病害控制等一系列代表病害流行生物学过程的子模型构成。模型采用了面向对象的程序设计方法,用C++语言编写,能以病害流行曲线图、空间分布图、数据列表等方式显示模拟结果。测试结果表明:模型能反映植物病害流行过程的本质规律,既可作为植物病害流行学教学工具,帮助学生理解病害流行的时、空动态规律和不同因子对病害流行的影响,也可以作为研究工具,对流行学的某些理论问题进行模拟研究     

代谢组学-植物病理学研究有力的生物分析工具

 代谢组学与基因组学、转录组学、蛋白组学共同构成系统生物学。代谢组学作为连接基因、蛋白与表型的重要桥梁,正逐步被应用于植物病理学研究的各领域。本文系统综述了代谢组学在植物侵染性病害的病原学、病害诊断、病原与寄主互作、植物抗病性、植物非侵染性病害和杀菌剂作用机制等领域应用的最新进展。将为采用代谢组学手段深入揭示生物或非生物因素作用下植物病害的发生规律、植物自身的防御机制以及外源药物的防病机理提供有益借鉴。代谢组学将通过解析生物标志物或代谢途径为生物表型相关蛋白功能的研究提供重要参考。     

基于PCR技术的植物病原菌分子定量检测技术研究进展

植物病原菌的菌源量是病害发生和流行的重要因子之一,对其精准的定量测定或检测可大大提高植物病害预测的准确性,本文对实时荧光定量PCR (qPCR)与数字PCR在植物病原菌定量检测、以及基于RNA水平的real-time PCR和基于核酸染料(EMA/PMA)与qPCR相结合的技术在植物病原菌活体定量检测中的应用进行了综述,并展望其在植物病害流行和预测中的应用前景。     

麦类赤霉病研究进展

由镰刀菌引起的麦类赤霉病是大麦和小麦最重要的病害之一。本文综述了近年来在麦类赤霉病致病病原菌种及分子鉴定、病原菌产毒及毒素化学型分子检测、大、小麦赤霉病病原菌种群结构、病原菌抗药性及新药剂研发、病害流行预测和品种抗病性研究等方面的进展。     

植物病害时空流行动态模拟模型的构建

一个描述在二维空间中单一种植或混合种植的植物群体内病害时、空流行动态的计算机随机模拟模型构建完成。模型由寄主、病原2个组分和病斑产孢、孢子传播、孢子着落、孢子侵染、病斑潜育、寄主生长、病害控制等一系列代表病害流行生物学过程的子模型构成。模型采用了面向对象的程序设计方法,用C++语言编写,能以病害流行曲线图、空间分布图、数据列表等方式显示模拟结果。测试结果表明,模型能反映植物病害流行过程的本质规律,既可作为植物病害流行学教学工具,帮助学生理解病害流行的时、空动态规律和不同因子对病害流行的影响,也可以作为研…     

14C-三唑酮在小麦幼苗上的吸收分布和影响因素

综述了近年来ＤＮＡ分子标记技术在植物真菌病害研究中的应用现状和潜力,内容涉及病原菌的种类鉴定,群体遗传,毒性变异,毒性基因迁移,菌源传播及植物抗病基因定位,克隆和标记辅助选择等植物病理学的诸多方面,列举了代表性应用实例,展望了ＤＮＡ分子技术在植物病理学研究中的广阔前景,提出了我国今后进一步开展有关研究的基本途径。     

几种常用植物病原细菌分子检测方法

植物病原细菌(phytobacteria)是植物上一类重要的病原菌,这些细菌能引起多种农作物、经济作物、花卉、树木及牧草上的病害。它的快速检测是病害防治、预测预报及植物检疫必不可少的重要工作。其中,以PCR为基础的分子检测技术的进步使植物病原细菌的检测更快速、灵敏和可靠。本文对近年来植物病原细菌分子检测技术进行介绍,尤其是应用广泛的ITS-PCR(intergenictranscribedspace-PCR)、ARDRA(amplifiedribosomalDNArestric-tionanalysis-PCR)、rep-PCR(repetitiveDNA-PCR)和实时荧光定量PCR(real-timequantitativePCR)技术,旨在促进我国植物病原细菌研究的快速发展。     

标记基因在植物病害发生和流行规律研究中的应用

标记基因在植物病害发生和流行规律研究中的应用莫才清（华中农业大学生命科学院武汉４３００７０）导致植物病害发生的生物因素有真菌、细菌等多种微生物。由于微生物个体微小，给植物传染性病害的发生和流行规律研究带来一定的困难。以往研究一直采用病情指数等指标来研...     

木霉菌生物防治作用机理与应用研究进展

木霉菌Trichoderma是国际上应用非常普遍的生防真菌.随着植物免疫的MAMPs(微生物互作分子模式)理论的发展,利用木霉菌防治病害和提高作物抗逆性机理研究进入了一个新阶段,尤其是系统生物学方法的应用,使得人们在"组学"尺度上认识木霉菌与植物和病原菌互作的本质成为可能,这将极大丰富木霉菌生物防治植物病害的理论基础.在我国建立木霉菌多样化应用技术途径是发挥木霉菌在农业可持续发展中作用的重要发展方向.本文重点介绍木霉菌生物防治分子机理研究的新进展.     

植物真菌和卵菌病暴发的起源和传播

传染病暴发在植物、动物和人群中很常见。除了少数已发展为流行病和大流行病外,在很大程度上大多数传染病暴发的原因仍未知,植物真菌和卵菌病暴发尤其如此。所有流行病和大流行病都是从局部暴发开始,然后蔓延到更广泛的地理区域,因此了解其初始暴发的原因对于有效预防和控制植物病害流行病和大流行病至关重要。该文首先描述疾病暴发的定义和检测,随后简要描述导致植物传染病暴发的主要原因,包括寄主植物、病原体及其相关的环境因素,以一种真菌和一种卵菌病原体为例简要概述宿主病原体系统,并强调分子工具在帮助揭示病原体的起源和传播及其暴发及大流行方面的作用。由于人为活动及气候的加速变化,植物病害暴发的可能性越来越大,最后提出应该如何应对其暴发。     

Molecular diagnostics for fungal plant pathogens

Accurate identification of fungal phytopathogens is essential for virtually all aspects of plant pathology, from fundamental research on the biology of pathogens to the control of the diseases they cause. Although molecular methods, such as polymerase chain reaction (PCR), are routinely used in the diagnosis of human diseases, they are not yet widely used to detect and identify plant pathogens. Here we review some of the diagnostic tools currently used for fungal plant pathogens and describe some novel applications. Technological advances in PCR-based methods, such as real-time PCR, allow fast, accurate detection and quantification of plant pathogens and are now being applied to practical problems. Molecular methods have been used to detect several pathogens simultaneously in wheat, and to study the development of fungicide resistance in wheat pathogens. Information resulting from such work could be used to improve disease control by allowing more rational decisions to be made about the choice and use of fungicides and resistant cultivars. Molecular methods have also been applied to the study of variation in plant pathogen populations, for example detection of different mating types or virulence types. PCR-based methods can provide new tools to monitor the exposure of a crop to pathogen inoculum that are more reliable and faster than conventional methods. This information can be used to improve disease control decision making. The development and application of molecular diagnostic methods in the future is discussed and we expect that new developments will increase the adoption of these new technologies for the diagnosis and study of plant disease.     

Systems analysis of wheat stripe rust epidemics in China

Stripe rust is the most destructive disease of wheat in China and shows long-distance spread with interregional epidemics. Systems analysis had been implemented by the epidemiology group at the China Agricultural University to study the epidemiology of this disease from field to regional levels. This paper reviews major achievements by this group from the 1970s to the present in this pathosystem in China. Field experiments were conducted to obtain necessary parameters for constructing various simulation models. Field-level models were generated to study the spatial and temporal disease developments, while region-level models were developed to study the disease long-distance spread, interregional epidemics and strategies for disease management. Interactions between host, pathogen and environment were also studied with modelling approaches to generate information on deployment of resistance for regional disease management.     

Botrytis cinerea in greenhouse vegetables: chemical,cultural, physiological and biological controls and their integration

Botrytis cinerea is an ubiquitous pathogen which causes severe losses in many fruit, vegetable and ornamental crops. The pathogen infects leaves, stems, flowers and fruits. The complexity of diseases caused by B. cinerea in greenhouses makes this pathogen one of the most important diseases of vegetable crops in greenhouse in many countries. In general, epidemics occur in cool and humid conditions, which favour infection and may also predispose the host to become susceptible. High relative humidity in the greenhouse and free moisture on plant surfaces are considered the most important environmental factors which influence infection by B. cinerea. In this review we specify the factors affecting the development of diseases incited by B. cinerea and discuss different approaches for its suppression. Chemical and non-chemical controls are outlined and their integration is discussed. Finally, achievements, gaps in knowledge, and future needs are indicated. The most common means for disease management is by application of chemical fungicides. Both spraying of fungicides and application of fungicides directly to sporulating wounds is practiced. However, high activity of several fungicides is being lost, at least in part, due to the development of resistance. As fungicides still remain an important tool for control of epidemics caused by B. cinerea, it is important to monitor populations of the pathogen for their resistance towards potential fungicides. Cultural measures can be a powerful means to suppress plant diseases in greenhouses where the value of crops is high and the farmers make considerable efforts during long cropping seasons. Such measures are usually aimed at altering the microclimate in the canopy and around susceptible plant organs, prevention of inoculum entrance into the greenhouse and its build up, and, rendering the host plants less susceptible to diseases. Calcium loading of plant tissues and alteration of nitrogen fertilization reduce susceptibility to Botrytis. Cultivars resistant to B. cinerea are not available. Another alternative methods to control B. cinerea is by means of biological control agents. At least one preparation is already available in the market and in many cases it was as effective as the conventional fungicides. A decision support system was recently developed for integration of chemical and biological controls. Adaquate suppression of B. cinerea diseases in greenhouse crops is an attainable goal. In our opinion this goal can be reached by considering the ecology of the pathosystem in its broader sense and by integration of all possible control measures. This implies optimization of plant nutrition, microlimate and control (cultural, biological, physiological and, if necessary, chemical) measures. Moreover, Botrytis management must be incorporated in a more holistic system that is compatible with insect control, crop production systems and profitability of the crop.     

Transgenic crops and beyond: how can biotechnology contribute to the sustainable control of plant diseases?

Disease resistance is without argument the best technological approach to control diseases in plants since no management input is required by the grower once the resistant variety has been planted. The biggest problems in using disease resistance lie in the facts that effective sources of resistance are not available for many important diseases, especially those caused by necrotrophic pathogens; and that pathogen populations adapt to the utilisation of novel sources of resistance, most notably for air-borne biotrophic pathogens. Several biotechnological approaches have been developed to produce disease resistant plants, the most recent known as NBT – New Breeding Technologies. This review focuses on recent advances in those technologies which adapt the knowledge obtained using molecular genetic approaches for the study of plant-microbe interactions to combat plant diseases.     

Direct and host‐mediated interactions between Fusarium pathogens and herbivorous arthropods in cereals

Fusarium head blight and fusarium ear rot diseases of cereal crops are significant global problems, causing yield and grain quality losses and accumulation of harmful mycotoxins. Safety limits have been set by the European Commission for several Fusarium‐produced mycotoxins; mitigating the risk of breaching these limits is of great importance to crop producers as part of an integrated approach to disease management. This review examines current knowledge regarding the role of arthropods in disease epidemiology. In the field, diseased host plants are likely to interact with arthropods that may substantially impact the disease by influencing spread or condition of the shared host. For example, disease progress by Fusarium graminearum can be doubled if wheat plants are aphid‐infested. Arthropods have been implicated in disease epidemiology in several cases and the evidence ranges from observed correlations between arthropod infestation and increased disease severity and mycotoxin accumulation, to experimental evidence for arthropod infestation causing heightened pathogen prevalence in hosts. Fusarium pathogens differ in spore production and impact on host volatile chemistry, which influences their suitability for arthropod dispersal. Herbivores may allow secondary fungal infection after wounding a plant or they may alter host susceptibility by inducing changes in plant defence pathways. Post‐harvest, during storage, arthropods may also interact with Fusarium pathogens, with instances of fungivory and altered behaviour by arthropods towards volatile chemicals from infected grain. Host‐mediated indirect pathogen–arthropod interactions are discussed alongside a comprehensive review of evidence for direct interactions where arthropods act as vectors for inoculum.     

Ecological Genomics and Epidemiology

The huge amount of genomic data now becoming available offers both opportunities and challenges for epidemiologists. In this “preview” of likely developments as the field of ecological genomics evolves and merges with epidemiology, we discuss how epidemiology can use new information about genetic sequences and gene expression to form predictions about epidemic features and outcomes and for understanding host resistance and pathogen evolution. DNA sequencing is now complete for some hosts and several pathogens. Microarrays make it possible to measure gene expression simultaneously for thousands of genes. These tools will contribute to plant disease epidemiology by providing information about which resistance or pathogenicity genes are present in individuals and populations, what genes other than those directly involved in resistance and virulence are important in epidemics, the role of the phenotypic status of hosts and pathogens, and the role of the status of the environmental metagenome. Conversely, models of group dynamics supplied by population biology and ecology may be used to interpret gene expression within individual organisms and in populations of organisms. Genomic tools have great potential for improving understanding of resistance gene evolution and the durability of resistance. For example, DNA sequence analysis can be used to evaluate whether an arms race model of co-evolution is supported. Finally, new genomic tools will make it possible to consider the landscape ecology of epidemics in terms of host resistance both as determined by genotype and as expressed in host phenotypes in response to the biotic and abiotic environment. Host phenotype mixtures can be modeled and evaluated, with epidemiological predictions based on phenotypic characteristics such as physiological age and status in terms of induced systemic resistance or systemic acquired resistance.     

Enquête sur les maladies fongiques de l'arachide (Arachis hypogaea) en Côte-d'Ivoire. I. Méthodes d'enquête et étude descriptive: les conditions culturales et les principales maladies

Groundnut diseases were surveyed in the various traditional cropping regions of Ivory Coast during 1982, 1983 and 1984. The methods used during the survey are described. A preliminary analysis of the results aimed at a characterization of a complex, multiple pathosystem is presented. The analysis especially focuses upon some foliar diseases, and particularly on rust, caused byPuccinia arachidis. The results show the great variability of the climates and of the agricultural techniques which are associated to groundnut cropping. The list of the fungal pathogens which affect groundnut is long: 16 have been identified during the survey, of which 6 are omnipresent in the various regions. A correspondence analysis was performed, allowing to describe the average development of the multiple pathosystem: groundnut-rust-leafsport-wilting fungi. Endemicity in tropical pathosystems is also analyzed in the case of the main foliar diseases (rust and Cercospora leafspots). More specifically, the epidemiology of groundnut rust in southern Ivory Coast is interpreted as regular, explosive epidemics developping on an endemic background. Every year epidemics develop in the northern and central areas too, most of their primary inoculum supposedly originating from the infested southern crops. Probably, intensification of agriculture will strongly favour rust disease.     

Trends in Theoretical Plant Epidemiology

We review trends and advances in three specific areas of theoretical plant epidemiology: models of temporal and spatial dynamics of disease, the synergism of epidemiology and population genetics, and progress in statistical epidemiology. Recent analytical modelling of disease dynamics has focused on SIR (susceptible–infected–removed) models modified to include spatial structure, stochasticity, and multiple management-related parameters. Such models are now applied routinely to derive threshold criteria for pathogen invasion or persistence based on pathogen demographics (e.g., Allee effect or fitness of fungicide-resistant strains) and/or host spatial structure (e.g., host density or patch size and arrangement). Traditionally focused on the field level, the scale of analytical models has broadened to range from individual plants to landscapes and continents; however, epidemiological models for interactions at the cellular level, e.g., during the process of virus infection, are still rare. There is considerable interest in the concept of scaling, i.e., to what degree and how data and models from one scale can be transferred to another (smaller or larger) scale. Despite assertions to the contrary, the linkages between epidemiology and population genetics are alive and well as exemplified by recent efforts to integrate epidemiological parameters into population genetics models (and vice versa) and by numerous integrated studies with an applied focus (e.g., to quantify sources and types of primary and secondary inoculum). Statistical plant epidemiology continues to rely heavily on the medical and ecological fields for inspiration and conceptual advances, as illustrated by the recent surge in papers utilizing ROC (receiver operating characteristic), Bayesian, or survival analysis. Among these, Bayesian analysis should prove especially fruitful given the reliance on uncertain and subjective information for practical disease management. However, apart from merely adopting statistical tools from other disciplines, plant epidemiologists should be more proactive in exploring potential applications of their concepts and procedures in rapidly expanding disciplines such as statistical genetics or bioinformatics. Although providing the scientific basis for disease management will always be the raison d’être for plant epidemiology, a broader perspective will help the discipline to remain relevant as more resources are being devoted to genomic and ecosystem-level science.